Tank-type circuit breaker

Abstract

A tank-type circuit breaker includes a cylindrical grounded tank in which an insulating gas is sealed, a vacuum valve insulated and supported in the grounded tank and including a movable-side contact and a fixed-side contact, a movable conductor electrically connected to the movable-side contact, a fixed conductor electrically connected to the fixed-side contact, a movable-side external conductor and a fixed-side external conductor disposed in a pair of bushings extending above the grounded tank, a movable-side frame electrically connecting the lower end of the movable-side external conductor to the movable conductor, and a fixed-side frame electrically connecting the lower end of the fixed-side external conductor to the fixed conductor. The fixed-side frame and the fixed-side external conductor are connected via at least two springs arranged in series along an extending direction of the fixed-side external conductor, so that the fixed-side frame is suspended and supported by the fixed-side external conductor.

1 . A tank-type circuit breaker, comprising:
 a cylindrical grounded tank in which an insulating gas is sealed;   a contact insulated and supported in the grounded tank and including a movable-side contact and a fixed-side contact;   a movable conductor electrically connected to the movable-side contact;   a fixed conductor electrically connected to the fixed-side contact;   a movable-side external conductor and a fixed-side external conductor disposed in a pair of bushings extending above the grounded tank, respectively;   a movable-side frame configured to electrically connect a lower end of the movable-side external conductor to the movable conductor;   a fixed-side frame configured to electrically connect a lower end of the fixed-side external conductor to the fixed conductor; and   a movable-side insulating support tube configured to insulate and support the movable-side frame in the grounded tank;   an annular portion formed of an annular plate and fixed at an outer peripheral portion to the fixed-side frame inside the fixed-side frame;   a rod fixed to a distal end portion of the fixed-side external conductor and extending in the extending direction of the fixed-side external conductor; and   an annular suppressing plate fixed at a central portion to a distal end portion of the rod, wherein   the fixed-side frame and the fixed-side external conductor are connected via at least two elastics arranged in series along an extending direction of the fixed-side external conductor, so that the fixed-side frame is suspended and supported by the fixed-side external conductor, and wherein   the elastics include a first elastic and a second elastic configured to generate, when compressed, a reaction force in a direction opposite to a compressed direction;   the first elastic is disposed between the fixed-side external conductor and the annular portion; and   the second elastic is disposed between the annular portion and the annular suppressing plate.   
     
     
         2 . The tank-type circuit breaker according to  claim 1 , wherein the elastics are coil springs or disc springs. 
     
     
         3 . The tank-type circuit breaker according to  claim 1 , wherein
 the contact is a vacuum valve.   
     
     
         4 . The tank-type circuit breaker according to  claim 1 , wherein
 the fixed-side frame includes an inner wall surface forming a cylindrical area;   the lower end of the fixed-side external conductor is inserted into the cylindrical area movably along an axial direction;   the at least two elastics are arranged in series from a lower end side of the fixed-side external conductor along the extending direction of the fixed-side external conductor; and   an outer wall surface of the fixed-side external conductor and the inner wall surface of the fixed-side frame are electrically connected via a current-carrying contact.   
     
     
         5 . (canceled) 
     
     
         6 . The tank-type circuit breaker according to  claim 4 , wherein
 the annular portion is a protrusion protruding from an inner wall surface of the fixed-side frame toward a central portion of the cylindrical area.   
     
     
         7 . The tank-type circuit breaker according to  claim 1 , wherein
 the annular portion is an annular plate joined to the fixed-side frame.